The invention relates to a device mounted in a craft, particularly in an aircraft or spacecraft, for recording data from a remote object, such as a part of the earth, or its atmosphere, or of another planet, moon or star, and particularly relates to a device such as a scanner for the production of line, infra-red multi-spectral data or panoramic images.
Devices are known in the art that are equipped with a primary element, such as a prism or mirror that rotates about a main axis and that forms a fixed angle of 45.degree. to that main axis, so that data can be recorded that are essentially situated in a plane perpendicular to the main axis. Generally, these devices are mounted in the craft so that the main axis is parallel to the direction of movement of the craft, causing data to be recorded in planes lying perpendicular to that direction of movement.
In line scanners the received electromagnetic radiation is directed onto a detector and after amplification, if any, is recorded on magnetic tape or is converted into light that is projected on to a secondary element, such as a prism or a mirror that rotates in phase with the primary element, and then recorded on a light-sensitive film.
In multi-spectral scanners, the electromagnetic radiation is directed onto a prism or a grid, and divided into different spectral zones, which are projected onto detectors and from them recorded onto magnetic tape.
In panoramic cameras the image received by the primary rotating element is projected onto light-sensitive film via a secondary element, rotating in phase with the primary element.
With the above devices it is not possible, however, to obtain straight away two sets of data of one and the same point of the object and, to attain this aim, several solutions have been proposed.
One of the solutions is to use two or more devices, whose main axes lie at some distance from each other with, for instance, each axis forming a specific angle with the direction of movement of the craft. This requires at least a doubling of the equipment.
According to another proposal, there are mounted on the main axis two prisms or mirrors that deviate from the angle of 45 degrees, but each, for instance, being at a respective side of the axis. Then receiving is not effected, however, any longer in planes but in conical surfaces, so that additional corrections must be effected.
In a panoramic camera a solution has been proposed in which the whole camera can oscillate about an axis perpendicular to the direction of movement of the craft. So as to generate and control this oscillation a complicated equipment is necessary, which would require a substantial amount of space and energy, and whose action must be compensated synchronously in the image taken up so as to enable elaborating the images in the proper form.